Anti-biofouling methods are known in the art. US2013/0048877, for instance, describes a system for anti-biofouling a protected surface, comprising an ultraviolet light source configured to generate ultraviolet light, and an optical medium disposed proximate to the protected surface and coupled to receive the ultraviolet light, wherein the optical medium has a thickness direction perpendicular to the protected surface, wherein two orthogonal directions of the optical medium orthogonal to the thickness direction are parallel to the protected surface, wherein the optical medium is configured to provide a propagation path of the ultraviolet light such that the ultraviolet light travels within the optical medium in at least one of the two orthogonal directions orthogonal to the thickness direction, and such that, at points along a surface of the optical medium, respective portions of the ultraviolet light escape the optical medium.